The invention generally relates to a method for driving an electric actuator unit and more particularly relates to a device for driving an electric actuator unit by means of a driving unit.
In modern motor vehicles, use is increasingly being made of electric actuator devices which must fulfill stringent safety requirements. For example in the case of an electric steering lock, the device must never lock while the vehicle is traveling.
An object of the invention is to drive an electric actuator device in such a way that a maximum degree of safety against inadvertent or incorrect driving of the actuator is achieved.
A method for achieving the object of the invention includes supplying an actuator unit having a voltage with a polarity which is dependent on the actuation direction with the result that the actuation direction can be reliably predefined. Furthermore, the actuator unit whose actuation direction is predefined by the polarity of the voltage which is supplied, at least in one of the actuation directions, is activated only if a further condition is fulfilled. This further condition can be, for example, in the case of an actuator unit designed for a steering mechanism lock, the fact that a stationary state of the vehicle is detected.
When the actuator unit is used for a steering lock, it is then actuated in such a way that it is effective in the direction of locking the steering only if it is supplied with voltage with a polarity which brings about actuation in the direction of locking the steering, and if, in addition, a signal indicating a stationary state of the vehicle is present.
The present invention can be applied wherever electric actuator units are to be actuated with a particularly high level of reliability. In particular, it can be used for motor vehicles where it should be possible to actuate numerous electric actuator devices only if specific travel state conditions are fulfilled and/or specific operating states are present.